A new study has found that pollutants found in diesel fumes may affect the honey bee’s ability to recognize floral odors.

The University of Southampton has conducted new research into honey bees, and have found that the pollutants commonly found in diesel exhaust can keep the bees from recognizing various floral scents. The diesel literally changes the way the flowers smell, and this is bad news for the bees, who use those smells to navigate and identify the plants from which they gather pollen. During the study, which was led by Dr Tracey Newman and Professor Guy Poppy, eight chemicals found in the oil of rapeseed flowers were exposed to air which had been contaminated with diesel fuel. The study found that aroma from six of the eight chemicals became reduced from the diesel fumes, while two chemicals lost their aroma altogether. When exposed to clean air, the aroma was unaffected.

The researchers believe that NOx gases, nitric oxide and nitrogen dioxide, are key factors in the process; they are components in diesel exhaust, and exposing the chemicals to them produces the same effect. “Honeybees have a sensitive sense of smell and an exceptional ability to learn and memorize new odours. NOx gases represent some of the most reactive gases produced from diesel combustion and other fossil fuels, but the emissions limits for nitrogen dioxide are regularly exceeded, especially in urban areas. Our results suggest that that diesel exhaust pollution alters the components of a synthetic floral odour blend, which affects the honeybee’s recognition of the odour. This could have serious detrimental effects on the number of honeybee colonies and pollination activity,” says Dr. Newman.

Honey bees contribute significantly to crop yield thanks to pollination. If they can’t find flowers, it’s trouble for all of us.

Professor Poppy adds: “Honeybee pollination can significantly increase the yield of crops and they are vital to the world’s economy – £430 million a year to the UK alone. However to forage effectively they need to be able to learn and recognize the plants. The results indicate that NOx gases—particularly nitrogen dioxide—may be capable of disrupting the odour recognition process that honeybees rely on for locating floral food resources. Honeybees use the whole range of chemicals found in a floral blend to discriminate between different blends, and the results suggest that some chemicals in a blend may be more important than others.”